Web accumulator including means for modifying tension in web passing therethrough



1966 c. HORNBERGER 3, 78,100

WEB ACCUMULATOR INCLUDING MEANS FOR MODIFYING TENSION IN WEB PASSINGTHERETHROUGH Filed March 20, 1964 5 Sheets-Sheet 1 I I l 45\ ,45 44 44r". r". I I 5] 48 441 43 4|- b= INVENTOR CLARENCE L- HORNBERGEFQ WI 2.2m

ATTORNEY 1966 c. 1.. HORNBERGER 3,

WEB ACCUMULATOR INCLUDING MEANS FOR MODIFYING TENSION IN WEB PASSINGTHERETHROUGH Filed March 20, 1964 5 Sheets-Sheet 2 Jig. 3 22 32 3o 24 65,Jzy.

I NVENTOR CLARENCE L- HORN BERGER BY l ATTORNEY Oct. 11, 1966 c. L.HORNBERGER 3,278,100

WEB ACCUMULATOR INCLUDING MEANS FOR MODIFYING TENSION IN WEB PASSINGTHERETHROUGH Filed March 20, 1964 5 Sheets-$heet 5 INVENTOR CLARENCE L-HORNBERGER BY MQM ATTOR EY Oct. 11, 1966 c. 1.. HORNBERGER 3,273,100

WEB ACCUMULATOR INCLUDING MEANS FOR MODIFYING TENSION IN WEB PASSINGTHERETHROUGH Filed March 20, 1964 5 Sheets-Sheet 4 INVENTOR CL AR ENCEL. HORNBERGER ATTORNEY 11, 1966 c. HORNBERGER 3,278,100

WEB ACCUMULATOR INCLUDING MEANS FOR MODIFYING TENSION IN WEB PASSINGTHERETHROUGH Filed March 20, 1964 5 Sheets-Sheet 5 F1 8 7 LI L2 INVENTORC L. ARENC E L. HORNBERGER BY mg.

ATTORNEY United States Patent 3,278,100 WEB ACCUMULATOR INCLUDING MEANSFOR MODIFYING TENSION IN WEB PASSING THERETHROUGH Clarence L.Hornberger, Lancaster, Pa, assignor to Armstrong Cork Company,Lancaster, Pa., a corporation of Pennsylvania Filed Mar. 20, 1964, Ser.No. 353,325 7 Claims. (Cl. 226-139) This invention relates to a webaccumulator or looper and more specifically to a drive mechanismtherefor. Web accumulators or loopers are used in the processing ofsheet material of substantial length to store or accumulate saidmaterial between continuous and intermittent operations. The stored oraccumulated material provides a source of continuous supply for eachoperation. Therefore, the material can be smoothly processed througheach operation without substantial adverse effect by an prior orsubsequent operation regardless of type, be it continuous orintermittent. For example, the sheet material at the inlet end of anaccumulator which has a full supply of such material may be stoppedwhile accumulated sheet material may be continuously withdrawn from theoutlet end of the accumulator until the supply of material within theaccumulator has been exhausted. Similarly, if an accumulator has a smallquantity of stored material, movement of the material at the outlet endof the accumulator may be stopped while material is continuously fedinto the accumulator until its storage capacity is entirely utilized.

Various types of accumulators are known. Basically, each accumulatorconsists of at least two substantially parallel frames wherein eachframe contains a plurality of spaced, freely rotatable, substantiallyparallel rollers mounted in a plane parallel to the plane of the frame.The frames are usually positioned so that each roller of one frame isparallel to each roller of the other frame. The material passesalternately over the rollers of each frame, thereby forming loopstherebetween.

The frames are mounted in a support assembly to allow relative movementof one or both with respect to the other. This is usually accomplishedby a cable and pulley or chain and sprocket arrangement attached to oneframe while the other frame remains fixed in the support assembly. Oneend of each chain or cable is attached to the movable frame while theother end, after passing over a sprocket or pulley, is attached to acounterweight having a weight which is usually less than that of themovable frame. The partially counter-balanced movable frame usually hassufiicient weight to bias movement thereof away from the fixed orstationary frame in an effort to keep the material in a taut conditionthroughout the accumulator at all times. The bias of the frame shouldnot be so great, however, as to cause a rupture in the sheet material.The movable frame is meant to be supported in a floating manner by thesheet material and to be free to move relative to the other frame inresponse to changes in the amount of sheet material in the accumulator.Where the material infeed exceeds the outfeed to the accumulator, thebiasing weight of the movable frame will cause an increasing amount ofmaterial to be pulled into the accumulator, with a resultant lengtheningof the material loops and movement of the movable frame away from thefixed frame. Should the material outfeed exceed the material infeed, theforce of the material on the movable frame will exceed the bias thereof,and the movable frame will be pulled in a direction toward the fixedframe as the length of the loops and, therefore, the amount of materialin the accumulator decreases. In some accumulators all frames are3,278,100 Patented Oct. ill, 1966 movable with respect to each other asshown in US. Patent 2,242,751, for example.

In US. Patent 2,631,847 there is disclosed an accumulator drive,mechanism having a one-way, over-riding clutch connecting the primemover, a motor driven speed reducer, to the sprocket shaft of a movableroller frame of carriage.

The primary drive motor in this patent is connected to the high speedshaft of a speed reducer. The speed reducer has a low speed shaft whichis connected to one side of the one-way, over-riding clutch. The speedreducer is chosen so that rotation of the high speed shaft will causethe low speed shaft to rotate but also so that the internal friction ofthe elements of the speed reducer will be sufficient to substantiallyprevent the low speed shaft from driving the high speed shaft to anappreciable degree. The opposite side of the one-Way clutch, beingconnected to the sprocket shaft of the movable frame, will, therefore,allow movement of this frame only to the extent allowed by the one-wayclutch, the speed reducer, and the motor.

In the normal operation of the device of US. Patent 2,631,847 describedabove, the primary motor normally is rotated in a direction which willallow the movable frame to move away from the fixed frame at a safe rateof speed. As long as the movable frame sprocket shaft does not try tooverride the speed reducer output shaft, the overriding feature of theclutch will allow said movable frame to float or to move in response todifferences in material infeed and outfeed.

As will be apparent, the one-way clutch and speed reducer provide asafety feature. Should the sheet of material break in the accumulator,the bias of the movable frame suddenly causes it to try to move awayfrom the fixed frame, which in turn causes the sprocket shaft to try tooverride the speed reducer output shaft. Such action will cause theone-way clutch to lock. Since the speed reducer cannot be drivensubstantially by its output shaft, the movable frame will move away fromthe fixed frame only as fast as the primary motor will allow the outputshaft of the speed reducer to rotate. The entire structure is therebyprotected from damage due to a run away movable frame caused by amaterial break. However, the one-way, over-riding clutch feature of thisdrive mechanism will still allow the desired floating action of themovable frame to keep the material in a taut condition in theaccumulator. In addition, the primary motor may be reversed wherein theclutch will lock and the movable bed may be positively moved toward thefixed bed for threading and other purposes.

It will be noted that the above-noted US. Patent 2,631,847 disclosesthat the counterweights may be varied depending upon the type ofmaterial being processed. It has been found, however, that manuallychanging the amount of counterweight is a difiicult and time consumingoperation due to the size and weight of the elements involved. Forexample, when heavy gauge, fibrous materials were processed, heavyweights had to be added to the movable frame while the amount ofcounterweight had to be decreased. This added weight was required toprovide enough force to cause the material to bend around the rollers tothereby keep the material in a taut condition in the accumulator. Thistaut condition is necessary to prevent fouling of the material. If toomuch weight is added, however, the support structure, chains, bearings,sprockets, clutch, speed reducer, and motor become overloaded. Thus,there are practical limits to the amount of weight which may be added.Conversely, in cases where light gauge materials were used, morecounterweight was required to prevent the weight of the movable framefrom tearing the sheet material.

An object of the present invention is to provide a drive .mechanism foran accumulator which may vary the effective force exerted by the movableframe on the sheet material to keep the sheet material in theaccumulator in a taut condition.

A further object of the present invention is to provide a drivemechanism for an accumulator which will substantially eliminate thenecessity of manually adjusting weights on a movable roller frame, thepossibility of damaging the accumulator due to such weight adustment,and other disadvantages of the prior art devices.

Further objects of the present invention will be readily apparent fromthe detailed discussion of the device noted below with reference to thedrawings wherein:

FIG. 1 shows a side view in elevation of a web accumulator and drivetherefor according to the invention;

FIG. 2 shows an end view in elevation of the web accumulator shown inFIG. 1 taken on line 2-2 thereof;

FIG. 3 shows a plan view of the accumulator shown in FIG. 1;

FIG. 4 shows an enlarged plan view of the drive mechanism of the webaccumulator of FIG. 1 taken on line 44 there-of;

FIGS. 5 to 7 show hydraulic circuit diagrams which may be used tocontrol the hydraulic booster motor associated with the drive mechanismof the accumulator of FIG. 1; and

FIG. 8 shows an electrical circuit diagram which may be used to controlthe drive mechanism of the accumulator of FIG. 1.

Referring now to FIG. 1, there is shown a web accumulator having anupright grid-like support structure 21. The support structure 21includes four corner posts 22, four intermediate horizontal beams 23interconnecting the corner posts 22, four upper horizontal beams 24-interconnecting the upper portions of the corner posts 22, and a lateralbeam 25. A pair of spaced, substantially parallel roller support plates26 are permanently fixed to and suspended from the upper portion of thegrid structure 21. Each plate 26 has a plurality of depending legs 27.The lower portion of each leg 27 houses a bearing 28, the axis of whichis substantially normal to the plate 26 and which is aligned with acorresponding bearing 28 on the opposite plate 26. A plurality ofrollers 29 are arranged in spaced, substantially parallel relationshipwith their axes being substantially normal toplates 26 and mounted inthe bearings 28 in each depending leg 27.

A pair of spaced, parallel shafts 30 are mounted in bearings 31 oneither side of the upper surface of the grid 21 along beams 24 andparallel to plates 26. A pair of spaced, chain sprockets 32 are securedto each shaft 30 near the respective ends thereof. A miter gear unit 33is connected to. the corresponding end of each shaft 30. A lateral shaft34 mounted in bearings 35 interconnects the miter gear units 33. One ofthe miter gear units 33 has an outwardly extending drive shaft which isconnected through a suitable bearing, sprocket, and chain drivearrangement, generally shown at 36, to a conventional hydraulic motor37, one-way clutch 38, speed reducer 39, and primary motor 40. Thisdrive arrangement will be explained in detail below with specificreference to FIG. 4.

As best seen in FIGS. 1 and 2, a sprocket 41 is attached to a lowerportion of each of the corner posts 22 directly below and in the planeof a corresponding sprocket 32. A continuous chain 42 extends aroundeach pair of corresponding, vertically aligned, co-planar sprockets.When so located, each chain 42 has two legs wherein one leg of eachchain faces the interior of the grid structure 21 and the other legfaces the exterior thereof.

A substantially horizontal frame 43 is located inside the grid structureand has each of its four corners attached to the inner leg of thenearest chain. The frame 43 has a plurality of spaced, horizontally andvertically aligned, upwardly extending projections 44 on either sidethereof. The projections 44 on each side of the frame lie in verticalplanes which are parallel to each other and to the planes of the plates26. However, the vertical planes of the projections 44 on either side ofthe frame 43 are located exteriorly of the planes of the plates 26.Thus, the distance between opposed projections 44 on frame 43 is greaterthan the distance between opposed legs 27 of plates 26. Each projection44 is provided with a hearing 45. A plurality of spaced, parallel,horizontal rollers 46 are mounted in bearings 45 in projections 44. Therollers 46 are parallel to but horizontally offset from rollers 29. Thespace between each of the rollers 46 on frame 43 and rollers 29 onplates 26 is sufficient to allow the rollers 46 to pass upwardly throughthe spaces between rollers 29 to a point where the lowest portion ofeach roller 46 lies above the uppermost portion of each roller 29 whenthe frame 43 is in its uppermost position. In this position the sheetmaterial 47 may be easily threaded through the accumulator 20 by passingsaid material over rollers 29 and under rollers 46. Loops of materialwill be formed when frame 43 moves to a lower position where the rollers46 have moved downwardly through the spaces between rollers 29.

The material 47 may be fed to the accumulator 20 by infeeder pinch rolls48 and 49 which are rotated by variable speed motor 50. Similarly, thematerial 47 may be withdrawn from the accumulator 20 by pinch rolls 51and 52 which are rotated by variable speed motor 53.

An elongated substantially horizontal counterweight 54 is associatedwith each sprocket shaft and extends parallel thereto within the gridstructure 21. Each counterweight 54 is attached near its respective endsto the outer leg of each of the chains 42 of the associated sprocketshaft 30. The counterweights 54 are positioned on the chains 42 so thatthey are at their uppermost positions when the movable roller frame 43is in its lowermost position as shown in FIGS. 1 to 3, for example. Itwill be apparent that the frame 43 and associated counterweights 54 willmove in opposite directions in adjacent vertical planes as the chains 42move around their sprockets 32 and 41.

Referring now to FIG. 4, there is shown the details of the drivearrangement. Shafts 30 and 34 are connected to miter gear units 33 bymeans of suitable shaft couplings. One of the miter gear units 33 hasdrive shaft 55 extending outwardly therefrom. A shaft 56, supported bybearings 57 and 58, is co-axially connected to shaft 55 by coupling 59.Sprocket 60 is mounted on shaft 56 between bearings 57 and 58. Asprocket assembly 61 having a small sprocket 62 co-planar with sprocket60 and connected to a large sprocket 63 is mounted on shaft 64. Shaft 64is parallel to shaft 56 and has its outer end mounted in bearing 65 withits inner end connected to one half of the one-way clutch 38. The otherhalf of oneway clutch 38 is connected to the output shaft 66 of speedreducer 39, the input shaft 67 of which is connected through coupling 68to shaft 69 of primary motor 40. Chains 70 interconnect sprocket 60 andsmall sprocket 62. Hydraulic motor 37 has an outwardly extending shaft71 which is parallel to shaft 64. The outer end of shaft 71 is mountedin bearing '72. A sprocket 73 is mounted on shaft 71 co-planar withsprocket 63. Chains 74 interconnect sprockets 63 and 73.

Referring now to FIG. 5, there is shown a basic hydraulic controlcircuit for the hydraulic motor 37. This circuit includes a sump 75, aconventional hydraulic pump 76, two conventional solenoid operatedvalves 77 and 78 in their de-energized positions, three adjustable,pressure relief valves 79, 88, and 81, a check valve 82 (which may beomitted if desired), and suitable connecting conduits to be described indetail below.

A conduit 83 leads out of a hydraulic fluid sump or reservoir 75. Pump76 is mounted in conduit 83. Conduit 83 connects with conduits 84 and85, each of which terminates in a port in valve bodies 86 and 87 ofvalves,

77 and 78, respectively. Valves 77 and 78 have movable valve cores 88and 89, respectively. Valve core 88 is provided with conduits 90, 91,92, and 93. Valve core 89 is provided with conduits 94, 95, 96, and 97.Conduits 98 and 99 extend through valve body 87 to hydraulic motor 37.Conduit 100 extends through valve body 86 to conduits 101 and 102.Conduit 101 connects with conduit 98. Conduit 102 contains pressurerelief valves 80 and 81, check valve 82, and leads to sump 75. Conduit103 extends through valve body 86, communicates with conduit 99,contains pressure relief valve 79, and communicates with conduit 192 ata point between pressure relief valves 80 and 81. Conduit 104 extendsthrough valve body 87 to conduit 102 at a point between valve 80 and thejuncture of conduits 102 and 103. Conduit 105 extends through valve body86 to conduit 104. Valves '79, 80, and 81 are adjustable and may be setat any desired working pressures as long as the pressure required toopen valve 81 is less than that of either of the valves 79 and 80.

As mentioned above, solenoid controlled valves 77 and 78 are shown inFIG. in their de-energized positions. In this case it will be apparentthat the pressure fluid supplied by pump '76 will be applied equally toboth sides of the hydraulic motor 37 through conduits 83, 84, 93, 103,99 and 83, 85, 95, 98. It will be noted that the pressure fluid suppliedby pump 76 may short circuit the motor 37 by flowing through conduits98, 101, 100, 92, 105, 104, 102 and 103, 99, 94, 104, 102, to sump 75.Thus, the pressure in the system will be approximately thatcorresponding to the setting of valve 81. The circuit shown in FIG. 5,therefore, represents a neutral condition wherein the hydraulic motor 37will not apply any force to the sprocket 63 or to the movable frame 43.The motor 37 in this case is free to move in either direction inresponse to movement of sprocket 63 and chains 74.

In FIG. 6, there is shown the same hydraulic circuit shown in FIG. 5except that the solenoid controlling valve 78 has been energized tochange the connections between certain conduits. It will be noted thatwith the valves 77 and 73 positioned as shown in FIG. 6, the pressurefluid supplied by the pump 76 is applied only to one side of the motor37 through conduits 83, 84, 93, 103, 99 and 83, 85, 97, 99. The pressureof the fluid supply to motor 37 in conduit 99 is greater than that offluid return from motor 37 in conduits 93 and 101, since the pressureexerted by the pump 76 on the hydraulic fluid and the pressure settingsof the relief valves 79 and 80 are greater than that pressure setting ofrelief valve 81. A force will, therefore, be applied by fluid motor 37through shaft 71, sprocket 73, and chains 74 to sprockets 63 and 62,chains 70, sprocket 60, shafts 55 and 56, miter gear units 33, shafts30, sprockets 32, and chains 42, which force will act against andthereby decrease the balancing effect of the counterweights 54. Thus,the effective weight and therefore the effective force of movable frame43 on the material 47 is increased. The arrangement shown in FIG. 6amounts to an add condition wherein the force normally exerted on thematerial by the frame 43 is effectively supplemented or increased. Thiscondition is necessary where materials of relatively thick gauge orthose having high resistance to bending are run through the accumulatorto keep said materials in a taut condition therein. It is to be notedthat the change in the amount of force applied is variable in relationto the variation in pressure settings of the adjustable valves 79, 80,and 81. It has been found that better accumulator operation is obtainedif the fluid pressure applied to motor 37 is insufficient for motor 37by itself to cause movement of the movable frame 43. It is conceivable,however, that under certain circumstances a fluid pressure which .willcause such movement might be desirable.

FIG. 7 shows a circuit wherein the solenoid controlling valve 77 isenergized and the solenoid controlling valve 78 is de-energized. In thiscase, it is apparent that 6 the pressure fluid supplied by pump 76 isapplied only to the side of the hydraulic motor 37 opposite to thatshown in FIG. 6. In FIG. 7, the pump 76 is connected to motor 37 throughconduits 83, 84, 91, 100, 101, 98 and 83, 85, 95, 98. A pressuredifferential is therefore created between the fluid supply in conduit 98to motor 37 and the return from said motor 37 in conduit 99, since thepressure exerted by pump 76 on the hydraulic fluid and the pressuresettings of relief valves 79 and 80 are greater than that pressuresetting of relief valve 81. Since the high pressure fluid is applied inthe circuit of FIG. 7 to the side of the motor opposite to that shown inFIG. 6, the force on the sprockets, chains, shafts, etc. resulting fromthe circuit of FIG. 7 will act in the opposite direction to that forcementioned with regard to FIG. 6. This force acting as a result of thecircuit of FIG. 7 will then tend to increase the balancing effect of thecounterweights 54, thereby decreasing the effect of the weight andtherefore the force exerted by the movable frame on the material 47.This arrangement is called a subtract condition in which the forcenormally exerted on the material 47 is counteracted or decreased. Such acondition is necessary in the case of highly flexible or thin gaugematerials to prevent tearing thereof in the accumulator. As mentionedabove, this force is variable, and best results are obtained if theforce exerted by motor 37 is insufficient to cause movement of themovable frame 43.

Referring now to FIG. 8, there is shown an electrical control circuitfor hydraulic supply pump 76, primary drive motor 40, and hydrauliccontrol valves 77 and 78. Electrical conductors L and L are connected toa suitable source of power, not shown. Conductor 106 connects conductorL to main control switch 107. When closed, switch 107 completes acircuit through a conductor connecting the motor of the hydraulic supplypump 76 to conductor L Closure of switch 107 also energizes relay 108 inconductor 109. Relay 108 closes normally-open switch 110 to providepower to the rest of the circuit including the primary motor 40. Thus,motor 40 may not be operated until power is supplied to the motor ofpump 76.

Conductor 111 is connected to switch 110. A conventional double pole,double-throw switch 112 has the correspondingly opposite terminal ofeach of the outer pairs of terminals connected by conductors 113 and 114to conductor 111. The other terminal of each of the outer pairs isconnected to conductor L by conductors 115 and 116. The intermediatepair of terminals of switch 112 are connected to motor 40 by conductors117 and 118 in such a manner that when switch blade 119, which ispermanently connected to conductors 117 and 118, contacts conductors 114and 116, the motor 40 rotates in a direction which will allow themovable frame 43 to move away from or toward the fixed rollers 29 in afloating manner in accordance with the operation of the speed reducerand clutch which has been previously explained. When switch blade 119contacts conductors 113 and 115, motor 49 will be driven in the oppositedirection in which the clutch 38 will lock and the movable frame 43 willbe positively raised.

Conductor 120 connects switch 121 to conductor 111. Conductor 122connects switch 121 and infeed pinch roll motor 50 to conductor LConductors 123 connect relay 124 to conductors 116 and L Relay 124controls normally-open switch 125. When closed, switch 125 connectsconductors 111 and 126. Conductor 127 connects conductor 126 andnormally-open switch 128. Switch 128 is controlled by relay 129 which isconnected to conductors 122 and L by conductors 130. Conductor 131 leadsfrom switch 128 to blade 132 of manually controlled, three-way selectorswitch 133. Conductor 126 extends from switch 125 to blade 134 ofselector switch 133. Both blades 132 and 134 of switch 133 will besimultaneously moved to one of three different contact positions markedA, N, and S. Solenoid 135 which controls movement of valve 78 isconnected by conductor 136 to the A contact position of blade 132 and toL Solenoid 137 which controls movement of valve 77 is connected byconductor 138 to the S contact position of blade 134 and to L The addposition of valves 77 and 78 shown in FIG. 6 may occur when the switch133 and blades 132 and 134 are located in the A contact position. Whenthe blades 132 and 134 are in the N contact position, a neutral positionof the valves 77 and 78 shown in FIG. occurs. When blades 132 and 134are in contact position S, a subtract position of the valves 77 and 78as shown in FIG. 7 may occur. Switch 139 is connected to conductor 126by conductor 140 and when closed will connect conductors 126 and 131.

As stated above, power cannot be applied to the primary motor 40 or tothe solenoid controlled valves 77 and 78 unless it is first applied tothe motor of the hydraulic pump 76. The relationship of the switch 112and the positions of blade 119 with regard to the direction of rotationof motor 40 as well as the effect thereof on frame movement have 'beenpreviously explained. It will be apparent that neither of the hydraulicvalves 77 or 78 may be energized unless blade 119 is in contact withconductors 114 and 116, primary motor 40 is running to allow the movableframe to float or to move downwardly at a controlled rate, and relay 124is energized. Thus, no additive or subtractive force may be applied tothe movable frame 43 when switch blade 119 contacts conductors 113 and115, and frame 43 is being raised positively by motor 40 through lockedclutch 38. No additive or subtractive force may be applied to themovable frame when the selector switch 133 is in the N or neutralposition. In each case neither of the solenoids 135 or 137 areenergized, and therefore, valves 77 and 78 remain in the neutralpositions shown in FIG. 5. The effect of the weight or force of theframe 43 on the material 47 remains unchanged.

When it is deemed to be necessary to provide additional force on thematerial, the selector switch 133 is moved so that its blades 132 and134 are in the A contact position. It is to be noted that valve 78 maynot assume its add position as shown in FIG. 6 unless infeeder switch121 is closed to cause infeeder motor 50 to run, relay 129 to beenergized, and switch 128 to be closed. The condition of these elementswill then complete a circuit through conductor 131, switch blade 132(when in contact with position A) to solenoid 135 which is thenenergized to move valve 78 to the position shown in FIG. 6. If desired,however, the effect of switch 121, relay 129, and switch 128 on valve 78may be eliminated by closing switch 139. In any event, when blade 134 ofselector switch 133 is in the A position, no circuit is completed tosolenoid 137, and valve 77 remains in its de-energized condition. Withthe solenoid of valve 78 energized and the solenoid of valve 77de-energized, the circuit and add condition of FIG. 6 are obtained. Inthis condition, the supplementary, additive, or increased effectiveforce is applied constantly to the material in the accumulatorregardless of the direction of movement of frame 43 caused solely bychanges in the length of material in the accumulator as long as themotor 40 is rotating to allow the frame 43 to move in a floating manneror in a downward direction at a controlled rate due to the over-ridingaction of the clutch 38.

When it is desired to decrease the effective force applied to thematerial, the selector switch 133 is moved so that blades 132 and 134are in contact positions S. In this case, solenoid 135 cannot beenergized due to the lack of a completed circuit thereto, and valve 78remains in its de-energized condition. However, solenoid 137 will beenergized due to the completed circuit through conductor 126, blade 134,and conductors 138 and L Valve 77 will then be moved to the positionshown in FIG. 7, and the resultant circuit shown therein will providethe subtract or decreased force condition on the material 47. Thisdecreased force condition will remain in effect regardless of thedirection of movement of frame 43 caused solely by changes in the lengthof material in the accumulator as long as motor 40 is energized torotate in the direction in which the over-riding action of the clutchwill allow the floating and controlled movement of the frame 43 inresponse to changes in length of said material.

Thus, the device of the present invention provides means to quickly andeasily adjust the effective force applied by a movable roller frame onvarious types of sheet material passing through an accumulator to keepsaid material in a taut condition while avoiding tearing thereof.

It is to be understood that the invention is not limited to theparticular electrical and hydraulic circuitry, valve arrangement, numberof valves, power transmission apparatus including shafts, couplings,chains, sprockets, gear units, etc., size, shape, relative position anddirection of motion of the accumulator frames, size and shape of theaccumulator and relative location of all the elements shown anddescribed. The details of these elements and arrangements may be varied,and equivalent elements may be substituted therefor.

Various modifications will occur to those skilled in the art withoutdeparting from the scope of the claims.

I claim:

1. A drive mechanism comprising primary drive means, means to be drivenin two directions, transmission means to drivingly connect said primarydrive means and said means to be driven, said transmission meansincluding coupling means connected to said primary drive means, saidcoupling means being of the type which may be driven by said primarydrive means but which is substantially incapable of driving said primarydrive means to an appreciable extent, and clutch means connecting saidcoupling means and said driven means, said clutch means allowing saidcoupling means, when said coupling means is moving in one direction, tooverride said driven means in said direction while allowing said drivenmeans to move freely in the other direction but providing asubstantially positive connection between said driven means and saidcoupling means should said driven means try to override said couplingmeans in said one direction, said clutch means also providing a positiveconnection between said coupling means and said driven means when saidcoupling means is moving in the other direction, and means associatedwith said transmission means to apply a force to be transmittedselectively in either direction to said driven means.

2. A drive mechanism according to claim 1 including control means forsaid drive mechanism.

3. An accumulator comprising at least two roller frames, support meansfor said roller frames including means for movably mounting at least oneof said roller frames whereby said movably mounted frame may be movedtoward and away from at least one of the other of said roller frames,bias means to urge said movably mounted roller frame away from saidother frame, primary drive means, transmission means, including couplingmeans connected to said primary drive means, said coupling means beingcapable of being driven by said primary drive means but beingsubstantially incapable of driving said primary drive means to anappreciable extent, said transmission means further including clutchmeans connecting said coupling means to said movable mounting means toallow said coupling means when said coupling means is moving in onedirection to override said movable mounting means in said directionwhile allowing said movable mounting means to move freely in the otherdirection but providing a substantially positive connection between saidcoupling means and said movable mounting means should said movablemounting means tend to override said coupling means in said onedirection, said clutch means also providing a positive connectionbetween said coupling means and said movable mounting means when saidcoupling means is moving in the other direction, and means associatedwith said transmission means to apply a force selectively in eitherdirection to said movable mounting means.

4. An accumulator according to claim 3 wherein said coupling meansinclude speed reducer means.

5. An accumulator according to claim 4 further comprising control meansfor said selective force-applying means.

6. A drive mechanism according to claim 1 in which said selectiveforce-applying means is hydraulic means.

7. An accumulator according to claim 5 in which said selectiveforce-applying means is hydraulic means.

References Cited by the Examiner UNITED STATES PATENTS De Ybarrondo226-42 X Laabs 74661 Wikle.

De Ybarrondo 242-55.01 Friedrich 74661 X Jacobsen 74661 Ferm 242-75.3 X

Gilbert 74661 Herr 242-5501 Peterson.

France.

M. HENSON WOOD, 111., Primary Examiner.

A. N. KNOWLES, Assistant Examiner.

3. AN ACCUMULATOR COMPRISING AT LEAST TWO ROLLER FRAMES, SUPPORT MEANSFOR SAID ROLLER FRAMES INCLUDING MEANS FOR MOVABLY MOUNTING AT LEAST ONEOF SAID ROLLER FRAMES WHEREBY SAID MOVABLY MOUNTED FRAME MAY BE MOVEDTOWARD AND AWAY FROM AT LEAST ONE OF THE OTHER OF SAID ROLLER FRAMES,BIAS MEANS TO URGE SAID MOVABLY MOUNTED ROLLER FRAME AWAY FROM SAIDOTHER FRAME, PRIMARY DRIVE MEANS, TRANSMISSION MEANS, INCLUDING COUPLINGMEANS CONNECTED TO SAID PRIMARY DRIVE MEANS SAID COUPLING MEANS BEINGCAPABLE OF BEING DRIVEN BY SAID PRIMARY DRIVE MEANS BUT BEINGSUBSTANTIALLY INCAPABLE OF DRIVING SAID PRIMARY DRIVE MEANS TO ANAPPRECIABLE EXTENT, SAID TRANSMISSION MEANS FURTHER INCLUDING CLUTCHMEANS CONNECTING SAID COUPLING MEANS TO SAID MOVABLE MOUNTING MEANS TOALLOW SAID COUPLING MEANS WHEN SAID COUPLING MEANS IS MOVING IN ONEDIRECTION TO OVERRIDE SAID MOVABLE MOUNTING MEANS IN SAID DI-